How do I get one alert to pop-up in Javascript instead of 4 of the same ones?

[system32]

In my current program I want to validate radio boxes. Now I dont want to write out an "if" statement to validate every single radio button checked so i thought it might be easier to make a for loop. With my current loop it shows the same error 4 times. How can I make it show up only once?

function radioCheck()
	{
		for (var i=1;i<=4;i++)
		{
			boxName = "pizzaSize" + i;
			if (!(document.pizzaForm[boxName].checked))
			{
				alert("You must select a pizza size");	
			}
		}
	}

Thanks

[WingedPanther]

Use a flag to keep track of whether you need to show the alert, and show the alert in an if statement outside the loop.

[system32]

Thank you for the reply. I am new to Javascript and am not sure how to use a flag to keep track of the alert. Could you please help me?

Thanks

[WingedPanther]

Just default bFlag to false before the loop, and in the loop set bFlag to true if you should show the alert.

[system32]

Thank you.

edit: Everything working now